JPS5863758A - Coating composition - Google Patents

Abstract

PURPOSE:A coating composition for steel plate or the like that contains a specific chelate reactive epoxy resin and an active organic curing agent, thus showing high adhesion and corrosion resistance and permitting simplification of derusting and primer treatment of steel plates. CONSTITUTION:For example, (A) (i) an acid of phosphorus bearing at least one P-OH bond such as phosphoric acid, its ester, such as butyl ester, or its salt as potassium salt, is made to react with (ii) an epoxy resin, preferably at a ratio of 0.05-0.4 equivalent of hydroxyls in the phosphoric acid to 1 equivalent of epoxy group in the resin to give a modified spoxy resin. Then, (A) the resultant resin is combined with (B) an active organic curing agent such as an aliphatic polyamine to give the objective composition.

Description

[Detailed description of the invention] The present invention relates to a novel coating agent for preventing corrosion of metals.

More particularly, the present invention relates to a corrosion-resistant coating containing a specific V-) reactive epoxy resin and an active organic curing agent. % of rust-free steel plates and rust-free steel plates have excellent adhesion and corrosion resistance to rusted steel plates or poorly treated steel plates, galvanized steel plates, aluminum, stainless steel, etc. The present invention relates to a coating composition.

Conventional epoxy resin paints are used as metal preservation paints in a wide range of fields because of their excellent corrosion resistance. However, in order to maintain its excellent corrosion resistance, it is necessary to carefully remove rust from the surface of the steel plate and thoroughly prepare the surface. If the surface is coated with insufficient surface treatment, poor adhesion will occur, and the corrosion resistance will also deteriorate significantly.

Therefore, it would be of great benefit if a coating film with good adhesion and excellent corrosion resistance could be obtained by simplifying the surface treatment of the steel plate or by coating it on a rusted steel plate.

The purpose of the present invention is to provide rust-free steel plates and mfm-free steel plates.
The purpose of the present invention is to provide a coating resin composition that has excellent adhesion and corrosion resistance even when the base treatment of the steel plate is simplified or when it is directly applied to a rusted steel plate.

The composition of the present invention comprises (A) an epoxy resin and at least one p-on as essential components.
A resin curable with a curing agent for epoxy resin obtained from a phosphorus acid having a bond, an ester or salt thereof (hereinafter abbreviated as precondensate) and an active organic curing agent for epoxy resin. .

Precondensation, which is an essential component of the composition of the present invention, involves combining an epoxy resin with phosphoric acids, hydroxyl group-containing phosphate esters, or their salts in the presence of a solvent or in a proportion that leaves epoxy groups. Obtained by heat treatment in its absence.

There are no particular limitations on the heating temperature, but it should be such that the epoxy resin does not decompose and the reaction is completed within a reasonable amount of time.
It is preferable to carry out the reaction at a temperature of 50 to 130°C.

The epoxy resin used here is limited to various types, such as those having more than one substituted or unsubstituted glycidyl ether group in the molecule, as shown by the formula, but preferably epoxy resins with a tk of 200~ Something around 1000 is good.

Examples of the phosphorus acid having at least one P-OH bond used in the present invention include orthophosphoric acid, metaphosphoric acid, pylori/ban, phosphorous acid, polyphosphoric acid, phosphonic acid,
Examples include phosphinic acid, and %V thiorthophosphoric acid is preferred.

Examples of phosphorus acid esters include the above-mentioned phosphorus acid esters, preferably furkyl esters having up to about 8 carbon atoms (those having one or more hydroxyl groups) and hydroxyalkyl esters, such as eva, ethyl, n Examples include those having groups such as -butyl, 2-ethylhexyl, hydroxyethyl, hydroxybutyl, hydroxyethyl, and hydroxypentyl, and mono- or di-phosphoric acid esters of n-butyl or 2-ethylhexyl are particularly preferred.

Examples of phosphorus acid salts include the above-mentioned phosphorus acid salts, such as potassium, sodium, lithium, calcium, zinc,
Examples include salts of aluminum, tin, barium, etc., especially potassium, sodium or calcium salts.
1J phosphate is preferred.

In the reaction between epoxy resin and phosphoric acids, the hydroxyl group of phosphoric acid is 0.05 to 0.01 per equivalent of epoxy group in the epoxy resin.
It is preferable to carry out at a ratio of g equivalent, preferably 0.05 to 0.4 equivalent, and the epoxy equivalent of the produced modified epoxy resin (precondensate) is preferably 3000 or less.

As the active organic curing agent used in the present invention, all the usual curing agents for epoxy resin coatings can be used, such as aliphatic polyamines, aromatic modified polyamines, aliphatic modified polyamines, polyamides, Examples include amino resins and carboxylic acids.

If necessary, other epoxy resins, diluents, solvents, coloring pigments, rust-preventing pigments, fillers, and other additives may be used in the composition of the present invention.

The planter composition of the present invention can be dried naturally to form a coating film, but if necessary, the desired coating film can also be obtained by forced drying by heating or the like.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Note that parts in the examples are based on weight.

Example 1 100 m of bisphenol A diglycidyl ether (epoxy equivalent = 240) and ADEKA GLYCILLOL ID-50
1 (epoxy equivalent = 500) and 6 parts of orthophosphoric acid were mixed and reacted at 80°C for 5 hours, and the resulting precondensate was designated as (11).

To 100 parts of precondensate (I), 30 parts of polyamide (amine value = !140) was added as an epoxy resin curing agent, and this blended resin was heated on a rusted steel plate (baked outdoors for one year,
Coated on a steel plate with floating rust removed, film thickness tSOμKl, 1
As a result of a comparative test of adhesive film performance after weekly room temperature curing and weekly room temperature curing, both adhesion and corrosion resistance were significantly superior to the comparative example.

Example 2 100 parts of bisphenol A diglycidyl ether (epoxy equivalent = 470), 5 parts of monoethyl phosphate, and 55 parts of xylene were mixed and reacted with stirring at 90'C for 4 hours, and the resulting precondensate was [ summer].

Precondensate [Summer: Adekahard f-mu of modified aromatic amine as an epoxy resin curing agent for 110011SK
-srs1 (y value = 280. Jiryu Kako! Co., Ltd. product name) was added to prepare a painted board using this blended resin in the same manner as in Example 1. The results are shown in Table 1. As shown, the adhesiveness and corrosion resistance were significantly superior to the comparative example.

In Example 3, 'Suf x / -ru ν diglycidyl ether (
100 parts of epoxy dll = 280), 50 parts of diglycidyl ether of bisphenol A/propylene oxide adduct (epoxy equivalent = 540), and 17 parts of dibasic potassium phosphate were mixed and the reaction was stirred at 110°C for 5 hours. The resulting precondensate is referred to as 〔厘〕.

Adeka hardener xa-zz of modified aliphatic amine as an epoxy resin curing agent for the precondensate [厘] joo part
A coated plate was prepared in the same manner as in Example 1 using this blended resin by adding 20 parts of 0 (amine value = 575, product name of Jiryu Kakogyo Co., Ltd.) and 50 parts of xylene, and the results were shown in Table IK. As shown, both adhesion and corrosion resistance were significantly superior to the comparative example.

Example 4 Novolak epoxy resin (epoxy equivalent = 180) 1
00 parts tohisphenol?・Diglycidyl ether of ethylene oxide adduct (epoxy equivalent = 310) 50
15 parts of dihydroxybutyl ester of birophosphoric acid and 50 parts of methyl isobutyl ketone were mixed at 70°C.
The precondensate obtained by performing the stirring reaction for a period of time is referred to as [W].

Precondensate (y): Modified polyamide adeca hardener 1n-2os as epoxy resin curing agent per 100 parts
(Amine value = 280. Asahi Denka Kogyo Co., Ltd. product name) 50
A coated plate was prepared in the same manner as in Example 1 using this blended resin and compared. As shown in Table 1, it was significantly superior to the comparative example in terms of both adhesion and corrosion resistance.

Example 5 100 parts of bisphenol A diglycidyl ether (epoxy equivalent = 470) and cresol novolac.
50 parts of epoxy resin (epoxy equivalent = 185), 10 parts of monoethyl phosphite, and amine 40iiS were mixed and reacted with stirring at 85°C for 5 hours.
V).

Precondensation-[V] Modified aliphatic amine 9 as epoxy resin curing agent per 100 parts Adeka Hardener-In-2
18 (Amine value = 575. Asahi Denka Kogyo Co., Ltd. product name)
11 parts and 50 parts of xylene were added, and a Km plate was prepared using this blended resin in the same manner as in Example 1 and compared. As shown in Table 1, the adhesiveness and corrosion resistance of the comparative example were significantly superior. .

Comparative Example 1 A blended resin prepared by mixing unmodified bisphenol A/diglycidyl ether (epoxy equivalent = 190) 1009 with 80 parts of polyamide (aniline number = 200) was applied to a rust-faced steel plate (baked outside for one year). Apply to round steel plate to remove floating rust, film thickness 150-200 μKL, 1 at room temperature.
Hardened for a week.

Comparative Example 2 A blended resin prepared by mixing 100 parts of unmodified bisphenol A diglycidyl ether (epoxy equivalent = 450) (solid content 5 ob) with 115 parts of Adeka Hardener 11fH-55 was applied to a rusted steel plate in the same manner as in Comparative Example 1. A coated plate was created by applying it to

Comparative Example 3 75 parts of unmodified bisphenol A diglycidyl ether (epoxy equivalent = 190) and bisphenol A
- 25 parts of diglycidyl ether (epoxy equivalent = 540) of propylene oxide adduct and ADEKA HARDENER-I! A compounded resin containing 0 part of -220S was applied to a rusted steel plate in the same manner as in Comparative Example 1 to prepare a coated plate.

[Coating film performance comparison test]

A coating film performance comparison test was conducted on the coated plates obtained in Examples 1 to 5 and Comparative Examples 1 to S. The results are shown in Table IK.

Claims (1)

[Scope of Claims] As an essential component (m) a resin that can be cured with an epoxy resin curing agent obtained from a phosphorus acid having at least one P-OH bond, an ester or salt thereof, and an epoxy resin; (B) A coating composition containing an active organic curing agent for epoxy resins.